Constant bearer

ABSTRACT

The invention relates to a constant bearer for moving loads, especially pipelines and similar, comprising a fastening part, a load-bearing part, and a spring system located between the fastening part and the load-bearing part for generating a constant bearing force, where the spring system displays a main spring assembly absorbing the load and a compensating device to compensate for changing spring forces of the main spring assembly. 
     With the objective of more easily transmitting the forces of the spring assembly and enabling improved compensation for the changing forces of the main spring assembly, two basic embodiments are proposed as a solution, where, in the first embodiment, an auxiliary spring assembly, as part of the compensating device, and the main spring assembly are located roughly perpendicularly to the bearing force, at least one cam part facing the main spring assembly is provided on the load-bearing part guided in sliding fashion over a travel path in the bearing force direction, and a load side of the main spring assembly is supported on the cam part of the load-bearing part. In the second embodiment, the auxiliary spring assembly is dispensed with and compensation for changing spring forces over a spring excursion is achieved via a cam part  13  with cam lever.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/067,896 filed Mar. 24, 2008, which is a national stage completion ofPCT/DE2006/001678, filed Sep. 21, 2006, which claims priority to DE 102005 045 736.3, filed Sep. 23, 2005.

DESCRIPTION

The invention relates to a constant bearer for moving loads, especiallypipelines and similar, comprising a fastening part, a load-bearing part,and a spring system located between the fastening part and theload-bearing part for generating a constant bearing force, where thespring system displays a main spring assembly absorbing the load and anauxiliary spring assembly to compensate for changing compressive forcesof the main spring assembly and where the main spring assembly displaysa main compression spring assembly located roughly perpendicularly tothe bearing force. In this context, the fastening part serves to fastenthe constant bearer to a base, and the load-bearing part to absorb theforce exerted on the constant bearer by the load. The invention furtherrelates to a constant bearer with a compensating device.

An auxiliary spring assembly is an embodiment of a compensating devicethat is designed to compensate for changing tensile and/or compressiveforces of the main spring assembly, usually from a centre position ofthe constant bearer. A generic constant bearer is disclosed inpublications FR 2 432 669 A1 and U.S. Pat. No. 2,535,305A, for example,where forces of the main compression spring assembly are in each casetransmitted to the load-bearing part via an envisaged lever system withtriangular lever.

A constant bearer with a compensating device is disclosed in U.S. Pat.No. 2,395,730 A, where, on the constant bearer, forces of the maincompression spring assembly are transmitted to the load-bearing part viaan envisaged lever system with triangular lever, by means of whichslight compensation can be performed.

GB 893 203 A discloses a constant bearer with a main spring assemblywhose spring forces are transmitted via a chain to a sprocket-wheelfixed on a triangular lever.

A non-generic constant bearer is, for example, disclosed in EP 0 188 654A1, where the constant bearer is designed as a constant hanger with aconstant tensile bearing force.

The object of the invention is to provide a constant bearer of the kindmentioned in the opening paragraph on which the forces of the springassembly are easier to transmit and which enables improved compensationfor the changing compressive forces of the main spring assembly.

According to the invention, the object is solved by the features of thecharacterising part of Claim 1. Given a customary, vertical arrangementof the main compression spring assembly, it is necessarily of relativelylong design, since high loads usually occur with pipelines, and requiresa great room height. A correspondingly smaller overall height of theconstant bearer can be obtained by arranging the main spring assemblyperpendicularly to the bearing force. Relative movement between the campart and the main compression spring assembly occurs due to displacementof the cam part as a result of the action of a load on the cam part.Depending on the geometry of the cam part, the main compression springassembly is compressed, thereby generating a corresponding spring force.The spring force acts on the load-bearing part via the cam part. Via thegeometry of the cam part, the spring force can be transmitted to theload-bearing part in a desired, path-dependent manner. Otherpossibilities for load transmission are, in principle, also open toconsideration in this context, such as lever or gear mechanisms.However, the cam part has the advantage that it is mechanically simpleand robust, and that its geometry offers possibilities for correctingspring inaccuracies of the main spring assembly. In this context, thecam part can be designed so exactly that changing compressive forces ofthe main spring assembly can largely be compensated for and an auxiliaryspring assembly can be dispensed with.

The auxiliary spring assembly can display auxiliary compression springsthat run parallel to the main compression spring assembly and act on theload-bearing part via auxiliary cam parts, where the auxiliary cam partsare located on independent pivoted levers. The position of the auxiliarycompression spring assemblies perpendicular to the bearing forcedirection, as well as the action of the auxiliary compression springassemblies on the load-bearing part via the pivoted levers, is alreadydescribed in EP 0 188 654 A1 and is therefore included in the content ofthis application in the embodiments described there. The parallelarrangement of the main spring assembly and the auxiliary springassembly achieves a very small overall height of the constant bearer,particularly since the two compression spring assemblies can lieparallel to each other, either one immediately above the other or asmall distance apart from each other.

To further enhance a compact design of the constant bearer, the pivotedlevers of the auxiliary spring assembly can be laterally routed past themain compression spring, a distance apart from each other, and mountedon the fastening part or on the housing, while they rest on theload-bearing part, preferably the cam part, in sliding fashion with anauxiliary cam side face of the auxiliary cam part. To this end, theauxiliary compression spring assembly can, on the load side, act on themiddle of the pivoted lever on a side of the pivoted lever facing awayfrom the auxiliary cam side face. One end of the above-described leverfor load-side guidance of a main compression spring can act on apivoting point on the fastening part that is located at the level of theside of the auxiliary compression spring assembly facing away from themain compression spring. This makes it possible to achieve anadvantageous, maximum lever length with the smallest possible overallheight of the constant bearer.

To completely solve the object, provision can, according to theinvention, be made on a constant bearer for moving loads, especially forpipelines and similar, that is provided with a fastening part, aload-bearing part, and a spring system located between the fasteningpart and the load-bearing part for generating a constant bearing force,where the spring system displays a main spring assembly absorbing theload and a compensating device to compensate for changing spring forcesof the main spring assembly on the load-bearing part, for thecompensating device to display at least one cam part, for the cam partto be coupled to the main spring assembly and the load-bearing part forload transmission from the main spring assembly to the load-bearingpart, and for the load-bearing part and the cam part to be movablerelative to each other on a non-linear path when the load-bearing partmoves along the travel path in such a way that complete compensation forthe changing spring forces of the main spring assembly on theload-bearing part can be achieved.

Thus, as in the previously described embodiments of the constant bearer,an additional auxiliary spring assembly as part of the compensatingdevice for compensating for the change in the spring forces issuperfluous. Elimination of the auxiliary spring assembly permits afurther reduction in the overall height of the constant bearer.Moreover, far fewer moving parts, and fewer components in total, arerequired in this case than for the previously described constantbearers. This facilitates assembly and permits simpler stocking.

The profile of the cam part or the non-linear path that enables completecompensation for the change in the spring forces over the springexcursion of the main spring assembly can be exactly calculated byiteration, e.g. using a spring characteristic of the spring system overthe travel path as the basis. The calculated profile can be transferredto the cam part, e.g. by means of programmable NC or CNC machines.Depending on the reasonableness of the costs and the technicallyfeasible perfection of the design of the non-linear path, compensationcan be achieved within a certain error range and thus possibly bevirtually complete.

The main spring assembly can act on the cam part in non-positive and/orpositive fashion for load transmission. To this end, a load end of themain spring assembly can, as described in more detail below, besupported on the cam part or mounted on the same in pivoting fashion.

The main spring assembly can preferably display a main compressionspring assembly arranged roughly perpendicularly to the bearing force.As mentioned above, this makes it possible to reduce the overall heightof the constant bearer.

In a development of the constant bearer, the cam part can display atleast one lever that is designed as a cam lever, mounted in pivotingfashion on the fastening part, and has two side faces lying oppositeeach other in its longitudinal extension, a first side face and a secondside face. The load side of the main spring assembly can be mounted onthe first side face in pivoting fashion, or supported on it. Moreover,the second side face can be designed as a cam side face on which theload-bearing part rests in sliding or rolling fashion. The cam side faceis the side face of the cam lever or the cam part, the profile of whichis designed in such a way that compensation can take place via therelative movement of the cam lever and the load-bearing part or,particularly in reference to the embodiments of the constant bearer withthe auxiliary spring assembly, via the relative movement of the cam partand the auxiliary spring assembly.

So that the relative movement can take place with the least possiblefriction, the load-bearing part can display a load roller with an axisof rotation perpendicular to the spring axis and perpendicular to thebearing force direction, and the cam side face can rest on the loadroller in rolling fashion in a plane perpendicular to the axis ofrotation.

The cam side face preferably rests on the load-bearing part with an areathat changes over the travel path and is deflected, by a changing amountover the travel path, away from an end of the load-bearing part designedas a load-bearing end for application of the load. Thus, the load rollerof the load-bearing part preferably contacts the cam side face at everypoint on the travel path in such a way that a force in bearing forcedirection can be transmitted via said side face to the load-bearing partfor retaining the load. The more the area is deflected away from theload-bearing end, the greater the component in bearing force directionof the spring force transmitted by the compression spring assembly. Theconstant bearer is preferably set in such a way that the maincompression spring assembly is compressed with a medium spring force ina middle travel position along the travel path, and a certain springforce in bearing force direction is transmitted to the load-bearingpart. If the main compression spring assembly is further relaxed as theload-bearing part progresses along the travel path, the spring force isreduced more than directly proportionally to its spring excursion. Tocompensate for this, the component in bearing force direction of thespring force transmitted to the load-bearing part can, by greaterdeflection of the area away from the load-bearing end by pivoting thepivoted lever(s), be increased in such a way that the bearing forceitself remains constant. This applies in the same way in the event ofgreater compression of the main compression springs, whose spring forceis then increased more than directly proportionally to their springexcursion, where, for compensation, the component in bearing forcedirection of the spring force transmitted to the load-bearing part can,by greater deflection of the area towards the load-bearing end bypivoting the pivoted lever(s), be reduced in such a way that the bearingforce itself remains constant.

The main spring assembly and/or the auxiliary spring assembly can, forexample, display several main compression springs or auxiliarycompression springs lying parallel to each other. Radially convergingmain compression springs and/or auxiliary compression springs can alsobe provided, where the cam part can in this case be designed as a bodywith a circular or preferably polygonal cross-section, on which theradially arranged main compression springs act on the load side. This isadvantageous if the moving loads do not move essentially in a line, aswith pipelines in the pipeline axis. The aforementioned auxiliary campart for the auxiliary spring assembly can display the same embodiments.

In an advantageous development of the constant bearer, the maincompression spring assembly displays two main compression springs, theload sides of which act symmetrically on the load-bearing part. Thesymmetry makes it possible to achieve an equilibrium of forces of thespring forces, avoiding additional moments of force. Moreover, as canparticularly be seen from the drawing, centering of the lever mechanismand self-stabilisation of the constant bearer can be achieved, thisenabling steady suspension or support of the load.

The fastening part can comprise a fastening device for fastening theconstant bearer on a base. Furthermore, the fastening part can display ahousing, which laterally encloses, and thus protects, the load-bearingpart and the spring system. The housing can furthermore display sidewalls encompassing retaining points and/or bearing points for the springsystem. The constant bearer can, as described in the prior art, bedesigned as a constant hanger. The constant bearer can, however, also bedesigned as a constant support with constant compressive bearing force.Since the bearing force, be it a compressive or a tensile force, can becompensated for by a spring system that is independent of gravity, theconstant bearer can also be used in any position in space.

In a preferred development of the main compression spring assembly, themain compression springs are located on a common spring axis.Furthermore, provision can be made for the main compression springs,lying opposite each other, to be supported on the cam part with theirload side and on the fastening part with a fastening side.

In one embodiment of the constant bearer, the cam part can display anassociated cam side face for each main compression spring. To this end,the cam part can display an opening, or be designed as a structuresurrounding an opening, where the springs act on the inner side of theopening. To this end, the inner sides should be designed as cam sidefaces, on which the load sides of the springs slide or move in someother way relative to the cam side faces. Since it is of less complexdesign and saves space, an embodiment of the constant bearer ispreferred in which the cam part is located between the main compressionsprings.

The cam part is expediently designed as a plate-like component withnarrow side faces, where the two cam side faces are formed by twoopposite, mirror-symmetrically arranged narrow side faces. This makes itpossible to achieve a particularly flat design of the constant bearer.Furthermore, as a result of the mirror-symmetrical arrangement, thespring forces can be transmitted to the cam part or to the load-bearingpart in a manner free of moments of force in the sum of the forces. Themain compression springs preferably have identical characteristics.Moreover, helical springs are preferred as the main compression springs.

In a development of the constant hanger with auxiliary spring assembly,the cam side faces can be separated from each other by a conical orroughly conical gap. A purely conical gap results in linear conversionof the travel path into the spring excursion, or of the spring forcesinto the bearing force, this being approximately sufficient. In animprovement of the profile of the cam side faces, deviations from theconical form can be provided as part of the compensating device in orderto achieve compensation for changing compressive forces of the mainspring assembly and/or, as described below, in order to achievecompensation of changing force directions, particularly changingcompressive force directions. This compensation can be so extensive thatan auxiliary spring assembly can be dispensed with. The transmission ofthe spring force can be set via the conical angle.

The main compression springs can be mounted in abutments, a first loadabutment or a second load abutment, on the load side and a fasteningabutment on the fastening side of the main compression springs.

To reduce the friction during relative movement between the load side ofthe main spring assembly and the cam part, it is possible, particularlyon the constant hanger with auxiliary spring assembly, to provide, onthe load side of the main compression springs, a first load abutmentwith a rotating roller having an axis of rotation perpendicular to thespring axis and to the bearing force direction, via which the maincompression springs are supported on the cam part in rolling fashion.

On a constant hanger without auxiliary spring assembly, provision canadvantageously be made for each main compression spring to have a camlever assigned to it. Furthermore, each main compression spring can besupported in the second load abutment in a supporting area of the firstside face of one of the cam levers. Advantageously, the cam levers can,in an area removed from the supporting area in the bearing forcedirection, be mounted on the fastening part in pivoting fashion in apivoting plane parallel to or on the spring axis and parallel to thebearing force direction.

The cam side faces of both cam levers can rest on the load-bearing partin sliding or rolling fashion. A load roller can be assigned to each camlever to this end. The load rollers can be located on a common loadroller axle in rotating fashion and are in this context expedientlypositioned on the load roller axle in individually rotating fashion.This permits a more compact design of the constant bearer. In thiscontext, the cam side faces are, in installation position and inoperation, expediently oriented in such a way that they are capable, inevery travel position of the load-bearing part along the travel path, ofexerting a force on the rollers with a force component F_(s) in bearingforce direction and a force component in the direction of spring axis fand perpendicular to force component F_(s). In this context, the forcecomponents in the direction of the spring axis can, thanks to apreferably symmetrical structure or thanks to a preferably symmetricalarrangement of the main compression springs, cancel each other out and,together with the attached load, ensure that the individual moving partsof the constant bearer are held together. The cam side faces can beprofiled in such a way that the force component in bearing forcedirection increases, from a lower travel position, in which theload-bearing part has performed maximum travel towards the load, to anupper travel position, in which the load-bearing part has performedmaximum travel away from the load, in continuous, non-linear fashion toa calculated extent in such a way that the changing spring forces of themain spring assembly are compensated for when the main spring assemblyis compressed and relaxed. This makes it possible to achieve a bearingforce on the attached load (not shown here) that remains constant overthe travel path.

Guidance of the main compression springs over their spring excursion isexpediently provided.

The guide can display a lever for each main compression spring, one endof which is mounted on the load side of the respective main compressionspring, and the other end of which is mounted on the fastening part inpivoting fashion at a pivoting point removed in the bearing forcedirection.

As a result, the main compression spring is guided over its springexcursion on the load side, in which context the main compression springperforms a pivoting movement via the lever on the load side owing to itsdesign, this movement being dependent on the lever length and on theposition of the pivoting point on the fastening part. A spring forcedirection, i.e. the direction in which the spring force of a compressionspring acts, can thus change accordingly. To remedy this, the fasteningside of the compression spring in question can, for example, be shiftedin relation to the fastening part, simultaneously with the pivotingmovement, in such a way that the spring axis of the main compressionsprings is merely displaced in parallel fashion. Considered to be moreadvantageous is the possibility of compensation for the changing springforces being accomplished by pivoting of the main compression springsvia the design of the cam part on which the main compression springassembly or, more generally, the main spring assembly is supported.Thus, in the embodiment of the constant bearer without auxiliary springassembly, the cam part can be designed in such a way that it compensatesfor the changes in the spring forces over the spring excursion, and thechange in direction of the spring forces, by pivoting the main springassembly. In the embodiment of the constant bearer with auxiliary springassembly, the cam part can be designed in such a way that it compensatesfor the change in direction of the spring forces by pivoting the mainspring assembly.

The lever assigned to a main compression spring can in each case bemounted in such a way that it runs parallel to the bearing forcedirection at a middle point of the spring excursion and/or a middlepoint of a travel path on which the load-bearing part can be displacedrelative to the fastening part. The aim of this is to minimisedeflection of the load end of the main compression springperpendicularly to the spring axis. The deflection can additionally bereduced by increasing the lever length.

To achieve symmetrical forces with lower frictional forces between themoving parts, two levers per main compression spring can preferably beprovided which, running parallel to each other and lying opposite eachother, are laterally mounted on the load end in pivoting fashion.

On the embodiments of the constant bearer without auxiliary springassembly, the lever can expediently form the cam lever at the same time.

In an expedient development of the constant bearer with auxiliary springassembly, the levers can be mounted in pivoting fashion on the firstload abutment. To this end, the first load abutment can display twocorrespondingly laterally arranged webs, bolts or the like that extendperpendicularly to the spring excursion and to the travel path, and onthe free ends of which a lever is in each case mounted in pivotingfashion. The pivoting point of the levers on the fastening part canexpediently be provided on a housing side wall, where the housing sidewall can display a bolt, located on the inner side and extendingperpendicularly to the spring excursion and to the travel path, on whichthe lever is mounted in pivoting fashion. To facilitate assembly of theconstant bearer, the lever can to this end display a mouth-like opening,by means of which it can be slid laterally over the bolt, where themouth-like opening opens in a directional component towards the loadside of the respectively assigned main compression spring or towards theend of the lever.

In another embodiment of the guide, the first and/or the second loadabutment can display a lateral, first guide projection, which extends,perpendicularly to the spring axis and to the bearing force direction,through a first guide slit provided in the fastening part and running inthe direction of the spring axis, and which rests in sliding fashion onthe inner side surfaces of the guide slit for guidance. This achievesdirect linear guidance of the main compression springs in the directionof the spring axis.

The first guide slit can be of limited longitudinal extension. Thislimitation can preferably serve as a stop for the first guide projectionfor limiting the spring excursion of the respectively assigned maincompression spring. In this way, the spring excursion can be limited toa range in which the change in the spring forces as a function of thespring excursion is as linear as possible. For setting the constantbearer to an anticipated load, provision can be made for the limit to beadjustable in the longitudinal direction of the slit. To this end,screw-type elements, for example, can be provided that can be slid andlocked in position in the first guide slit. The first guide slit canexpediently also be designed as a slot that can simultaneously limit amaximum possible spring excursion.

In a development, the constant bearer can preferably display a settingdevice for setting a pre-tension of the main spring assembly. To thisend, the fastening abutment provided on the fastening side and/or thefirst and/or second load abutment of the main compression springs can bedesigned to slide and be fixed in position in the direction of thespring axis. In a customary embodiment, the abutments can in each caseexpediently display an abutment disc on which the main compressionspring is supported at the face end. The abutment disc can be adjustablein sliding fashion in the direction of the spring axis by means of ascrew connection. To facilitate mounting of the main compression springsin the abutments, the abutments can in each case display a sleeve thatextends from the abutment disc towards the main compression springs,surrounding them at their ends or extending into them at their ends. Theends of the main compression springs should expediently rest laterallyon the sleeve. This prevents the main compression springs from laterallyslipping off the abutment discs.

The abutment disc of the fastening abutment can display a concentricthrough-hole with an internal thread, through which a bolt with anexternal thread mating with the internal thread is passed, where theface end of the bolt facing away from the main compression springs ismounted on the fastening part in rotating fashion. The abutment disc canthus be displaced by turning the bolt. The spring force acting on theabutment disc prevents the abutment disc from also rotating when thebolt is turned. Provision can additionally be made for anchoring of thespring in the abutment to be provided in the circumferential directionof the abutment disc.

To achieve easy turning of the bolt, the face end of the bolt facingaway from the main compression spring can display a journal with asmaller diameter than the bolt, which extends concentrically in thelongitudinal direction and which, in installation position, extendsthrough a bearing opening adapted to it in the fastening part and isprovided with an operating end projecting beyond the bearing opening forapplication of a tool, while the face end of the bolt is supported onthe edge of the bearing opening. This operating end can, for example, bedesigned as a screw head, a hand wheel or a hand lever. To indicate thenumber of turns of the operating end, a scale running around the bearingopening, or a counter, can be provided on the outside.

In a preferred development, the face end of the bolt facing towards theload-bearing part in installation position can display a laterallyprojecting stop running against the bearing opening to limit theadjusting travel. This stop can, for example, be designed as a lockingsplit-pin projecting beyond the outer perimeter of the bolt. As a resultof displacement of the abutment in the direction of the spring axis, thespring is correspondingly compressed or relaxed on its spring excursion,meaning that a certain preload can be set in this way, with which themain compression spring acts on the load-bearing part. The preload canbe set in such a way that it corresponds to an anticipated load in aposition of rest. Presetting and adjustment via an additional adjustingdevice is thus possible, as in EP 0 188 654 A1. The teaching of EP 0 188654 A1 relating to the fundamental method for presetting and adjustingthe main spring assembly is therefore included in the content of thisapplication.

To indicate the displacement of the abutment disc, the abutment disc candisplay a lateral, second guide projection which, in order to indicatethe relative position of the abutment disc, extends through thefastening part through a second guide slit extending in the direction ofthe spring axis. The second guide slit can be provided in a housing sidewall of the fastening part in this context. A scale or the like forreading-off the position of the lateral, second guide projection can beprovided on the outer side of the housing side wall, adjacent to theslot. Owing to the simple, almost linear relationship between springexcursion and spring force, the scale can also be designed as a loadscale for reading-off a spring force preset as a preload. To improve itsguidance, the abutment disc can also display two lateral, oppositeprojections that extend through two second guide slits. As a result, acertain presetting of the preload can be read-off on two sides. Thesecond guide slit can expediently be designed as a slot, which cansimultaneously limit the maximum possible displacement of the abutmentdisc.

For guidance, the cam part can display a lateral, third guide projectionthat extends, perpendicularly to the spring axis and to the traveldirection, through a third guide slit, provided in the fastening partand running in the direction of the spring axis, and rests in slidingfashion on the inside surfaces of the third guide slit. In this context,the third guide projection can also extend on both sides of the cam partinto two third guide slits running parallel to each other. The thirdguide slits can be located in housing side walls. The third guide slitscan likewise be designed as slots. On the outer side of the housing sidewalls, scales designed as distance scales can be provided along thethird guide slit(s) to indicate the travel path of the guideprojection(s). Furthermore, according to the prior art, particularlyaccording to EP 0 188 654 A1, an adjusting device can be provided forsetting and readjusting a pre-tension of the main compression springassembly and a zero position of the cam part on its travel path. Topermit quick and simple reading-off of the deflection of the third guideprojection from its zero position in normal operation, it is possible toprovide, in addition to the distance scale or instead of the distancescale, markings that indicate the zero position and the permissibledeflection from the zero position, for example. Symbols and/or colouredmarkings can be used for this purpose, for example.

As mentioned above, the constant bearer can be used as a constant hangeror as a constant support. If the constant bearer is used as a constanthanger, the fastening part with a fastening device is located at the topwhen the constant bearer is in its installation position, theload-bearing part for attaching the load being at the bottom. Theload-bearing part thus acts on an attached load via a constant tensilebearing force. The fastening device can expediently display straps andeyes for suspension from a base, on which the constant bearer designedas a constant hanger can preferably be located in pivoting fashion. Viaa pivoting movement, the constant bearer can thus follow the movementpath of the moving loads, meaning that the bearing force directionremains essentially constant in relation to the constant bearer. If, forexample, the constant bearer is used as a floor-mounted constantsupport, the fastening part is at the bottom in installation positionand connected to the floor as the base, while the load-bearing part islocated at the top to receive a load, such that the spring system actson a deposited load with a constant compressive bearing force. However,the functional principle based on the spring system also makes itpossible to use the constant bearer as a constant hanger or a constantsupport in any position in space.

As can also be seen directly from the drawings below, the constantbearer can be of symmetrical design.

In order to accommodate very great loads, for example, one maincompression spring, two symmetrically arranged main compression springs,or every main compression spring, can be expanded to encompass two ormore main compression springs in the first embodiment of the constantbearer with auxiliary spring assembly and/or the second embodimentwithout auxiliary spring assembly. These main compression springs canpreferably be arranged parallel to each other and, also preferably, oneabove the other or alongside each other as regards the travel path. Themain compression springs can also be arranged coaxially to each other,where a main compression spring located coaxially on the insideexpediently displays an outside diameter that is smaller than the insidediameter of a main compression spring located on the outside. In thesame way, the auxiliary spring assembly provided can display auxiliarycompression springs arranged coaxially to each other.

The invention is described in more detail below based on two practicalexamples with an associated drawing. The Figures show the following:

FIG. 1 A perspective view of a first embodiment of a constant bearer,without front housing side wall, front right lever and connecting strap,

FIG. 2 a A side view of the constant bearer according to FIG. 1, in anupper travel position,

FIG. 2 b A side view of the constant bearer according to FIG. 2 a, butin a middle travel position,

FIG. 2 c A side view of the constant bearer according to FIG. 2 b, butin a lower travel position,

FIG. 3 A detail according to FIG. 2 a, but with partial sections,

FIG. 4 A detail according to FIG. 2 a, but with additional front housingside wall,

FIG. 5 a A perspective view of a second embodiment of the constantbearer, with a load-bearing part in the upper travel position andwithout front housing side wall and connecting strap,

FIG. 5 b A perspective view of the second embodiment according to FIG. 5a, but in the lower travel position,

FIG. 6 a A side view of the constant bearer according to FIG. 5 a,

FIG. 6 b A side view of the constant bearer according to FIG. 6 a, butin a middle travel position,

FIG. 6 c A side view of the constant bearer according to FIG. 5 b,

FIG. 7 a A perspective side view of the constant bearer, with fronthousing side wall and inserted transport lock,

FIG. 7 b A perspective side view of the constant bearer according toFIG. 8 a, without inserted transport lock, and

FIG. 8 A partial side view of the constant bearer according to FIG. 6 a,without front housing side wall.

FIGS. 1 to 4 show various views of a first embodiment, and FIGS. 5 to 8of a second embodiment, of a constant bearer 1 designed as a constanthanger for moving loads (not shown), especially pipelines and similar(not shown), comprising a fastening part 2, a load-bearing part 3, and aspring system 4 located between fastening part 2 and load-bearing part 3for generating a constant bearing force F. In both embodiments, thespring system displays a compensating device K to compensate forchanging compressive forces of main spring assembly 9.

In the two embodiments illustrated here, constant bearer 1 is designedas a constant hanger with fastening part 2 at the top in installationposition and load-bearing part 3 extending downwards for attaching theload not shown here. Fastening part 2 displays a housing 5 with sidewalls 6, of which the front side wall is in each case omitted in FIGS. 1to 3 and 5 to 6 for greater clarity of the drawings. The two larger sidewalls 6 are connected to an upper connecting strap 7, which displays afastening hole 8 for connection to and suspension from a base not shownhere. Housing 5 surrounds spring system 4 and load-bearing part 3laterally and on the top side, where load-bearing part 3 can bedisplaced downwards, out of housing 5, in a travel direction v over atravel path w, and back into the housing.

The first embodiment of constant bearer 1 is first described in moredetail below, followed by the second embodiment.

In the first embodiment of constant bearer 1, spring system 4encompasses a main spring assembly 9 absorbing the load and, as part ofcompensating device K, an auxiliary spring assembly 10 to compensate forchanging compressive forces of main spring assembly 9. The two springassemblies 9, 10 are arranged parallel to each other and perpendicularlyto travel direction v, i.e. in the horizontal direction in installationposition of the embodiment of constant bearer 1 shown here. This permitsa compact design of constant bearer 1. Main spring assembly 9 andauxiliary spring assembly 10 act on load-bearing part 3 on the loadside, being supported on housing 5 on the fastening side. Main springassembly 9 displays a main compression spring assembly 9 a with twosymmetrically arranged main compression springs 11, which are locatedopposite each other with their load side resting on a cam part 12 offastening part 2, where cam part 12 is located between main compressionsprings 11 and displays an associated cam side face 13 for each maincompression spring 11.

Cam part 12 is designed as a plate-like component with an essentiallytriangular basic shape, where cam side faces 13 are formed by two narrowside faces of the plate-like component.

Cam side faces 13 are thus separated from each other by a roughlyconical gap that widens towards the top. In this instance, maincompression springs 11 are each guided in abutments 14, 15, a first loadabutment 14 on the load side and a fastening abutment 15 on thefastening side. Mounted in first load abutment 14 in rotating fashionperpendicularly to travel direction v and to spring axis f is acylindrical roller 16, via which the respective main compression spring11 is supported in rolling fashion on cam side face 13 assigned to it.Mounted in pivoting fashion on the same axle as roller 16 and on eitherside of roller 16 is a lever 17 for guiding the load-side end of therespective main compression spring 11 on first load abutment 14. Theother end of lever 17 is mounted in pivoting fashion at a pivoting pointremoved in bearing force direction t on the inner side of housing 5,where housing 5 displays a bolt 18, located on the inner side andextending perpendicularly to spring axis f and to travel direction v,onto which lever 17 can be laterally slid via a mouth-like opening 19provided at the end. Opening 19 has a directional component pointingtowards the other end of lever 17, meaning that the lever, the design ofwhich is such that it is exposed to tensile stress in operation, issecurely mounted in opening 19. The mouth shape of opening 19 isselected for easy connection of lever 17 to housing 5 in pivotingfashion when assembling constant bearer 1.

FIGS. 2 a to 2 c illustrate the travel of load-bearing part 3 into threepositions: an upper travel position in FIG. 2 a, a middle travelposition in FIG. 2 b, and a lower travel position in FIG. 2 c. Byload-bearing part 3 moving out of housing 5, from the upper travelposition towards the lower travel position, constant bearer 1 reacts tomovement of the loads (not shown) attached to load-bearing part 3 awayfrom constant bearer 1. In this context, main compression springs 11 arecompressed by rollers 16 rolling on cam side faces 13 of cam part 12,thereby exerting a correspondingly increasing spring force onload-bearing part 3, and thus on the moving load, via cam part 12. Sincethe load sides of main compression springs 11 are in each case guidedvia associated levers 17, the load ends of main compression springs 11are guided along a corresponding pivoting path, where lever 17 runs intravel direction v when in the middle travel position illustrated inFIG. 2 b. The resultant deviation from linear transmission of the springforce in the direction of travel direction v, which cannot be exactlyillustrated in the drawing because of its small magnitude, is correctedby a correspondingly adapted profile of cam side faces 13.

Auxiliary spring assembly 10 displays auxiliary compression springassemblies 20, which run parallel to main compression springs 11 and,via auxiliary cam parts 21, act on cam part 12 and on load-bearing part3, where auxiliary cam parts 21 are located on independent pivotedlevers 22. In this context, pivoted levers 22 of auxiliary compressionspring assembly 20 are arranged parallel to each other and a distanceapart, laterally to main compression spring 11 and auxiliary compressionspring assembly 20, are mounted in pivoting fashion on housing 5 at thelower end, and supported roughly in the middle on first load abutment 14of auxiliary compression spring assembly 20.

In the upper travel position, an upper end of an auxiliary cam side faceof the auxiliary cam part of pivoted levers 22 acts on the upper part ofcam part 12. At this point, cam part 12 in each case displays a roller16 for reducing friction during relative movement between cam part 12and pivoted lever 22, where rollers 16 are mounted on cam part 12 in amanner permitting rotation perpendicular to travel direction v and tospring axis f. When cam part 12 or load-bearing part 3 moves from theupper travel position (FIG. 2 a) to the lower travel position (FIG. 2c), auxiliary compression spring assembly 20 exerts different forces oncam part 12 via auxiliary cam parts 21.

In the upper travel position, auxiliary spring assembly 10 acts as atensile force with an upward force component in travel direction v, thusintensifying the relatively low tensile force of main compression spring11 acting on the load. In the middle travel position, the auxiliaryspring assembly acts perpendicularly to the travel direction and not intravel direction v, in which context the forces in the auxiliary springassembly cancel each other out. Main compression spring 11 acts on campart 12 with the previously set preload in this context. This is alsoreferred to as the zero position. In the lower travel position,auxiliary spring assembly 10 acts as a compressive force with a forcecomponent in travel direction v, thus counteracting the relatively hightensile force when the main compression springs are in compressed state.Given exact setting and design of cam parts 12, 21, the profile of theresultant force in travel direction v arising from the sum of all forcesexerted on load-bearing part 3 by spring system 4 corresponds exactly tothe ideal, linear characteristic of main compression springs 11. In thisway, the force of main compression springs 11 with spring-inducedtechnical deviation is compensated for to obtain a constant supportingforce.

Further measures are taken for exact guidance of main compressionsprings 11, as well as for setting and indication. To this end,abutments 14, 15 display an abutment disc 23 with a sleeve 24, extendinginto the interior of main compression springs 11, where the end sides ofthe main compression springs rest on sleeves 24.

Fastening abutment 15 of main compression springs 11 can be displacedaxially to set a pre-tension of main compression springs 11. This isillustrated in more detail in FIGS. 3 and 4, based on detail III/IVaccording to FIG. 2 a. In FIG. 3, the detail additionally shows partialsections, whereas FIG. 4 additionally shows front housing side wall 6,which is omitted in FIG. 2 a. Abutment disc 23 of fastening abutment 15is provided with a concentric through-hole 25 with an internal thread26, through which a bolt 27 with an external thread 28 mating withinternal thread 26 is passed, where the face end of bolt 27 facing awayfrom main compression spring 11 is mounted on side wall 6 of housing 5in rotating fashion. For this purpose, this face end of bolt 27 displaysa journal 29 with a smaller diameter than bolt that extendsconcentrically in the longitudinal direction, where journal 29 extendsthrough a bearing opening 30 adapted to it in side wall 6 and has anoperating end 31 projecting beyond the bearing opening on the outsidefor application of a tool not shown here. Bolt 27, journal 29 andoperating end 31 are of one-piece design and secured by a retaining ring32 to prevent them from falling out of bearing opening 30 in unloadedstate. By turning operating end 31 or bolt 27, fastening abutment 15 isdisplaced in the direction of spring axis f via the meshing threads ofabutment disc 23 and bolt 27, the associated main compression spring 11thus being given a desired pre-tension. As a result, spring system 4 canbe set to a certain load, as described in principle in EP 0 188 654 A1.For limitation on the one side, abutment disc 23 can run up against sidewall 6, while on the other side, on the free end of bolt 27, a stop hole33 is provided, through which a locking split-pin (not shown) can beinserted, which can simultaneously act as a stop.

Abutment disc 23 of fastening abutment 15 of main compression springs 11is provided with a lateral, second guide projection 34, which extends,perpendicularly to spring axis f and to travel direction v, through asecond guide slit 35 provided in side wall 6 and running in thedirection of spring axis f, and which rests in sliding fashion on theinner side surfaces of second guide slit 35 for guidance, as canparticularly be seen in FIGS. 1 and 4. Provided on the outside on sidewall 6 is a load scale 38, shown in FIG. 4, on which the setting of thepreload of main compression spring 11 can be read off directly via thedisplacement of second guide projection 34 in second guide slit 35. Forthis reason, the scale of load scale 38 is in the unit of force“Newton”, as not explicitly shown here. The set preload can thus be readoff directly. Particularly in the event of little compression of maincompression spring 11, the guidance of second guide projection 34 insecond guide slit 35 additionally prevents fastening abutment 15 fromrotating with bolt 27 when setting the pre-tension by turning bolt 27.

In similar fashion, guidance of cam part 12 in travel direction v isprovided, where a third guide slit 36 is provided in each of theopposite, large side walls 6 of housing 5, in each of which a thirdguide projection 37 is guided in sliding fashion. Third guide slit 36 isdesigned as a slot, the ends of which simultaneously serve as a stop forlimiting the travel path of fastening part 2. Third guide projection 37moreover extends beyond third guide slit 36 and serves as a marker foradjusting the pre-tension of main compression springs 11 in relation toa certain load, as described in more detail in EP 0 188 654 A1, but notshown here for the sake of clearer presentation of the parts of springsystem 4 lying behind it.

The shape of pivoted lever 22 displays a discontinuity 39 in the sectionbetween the mounting point on a large side wall 6 of housing 5 and thestart of auxiliary cam part 21, via which pivoted lever 22 acts on campart 12. By means of this discontinuity 39, pivoted lever 22, when inits lower travel position (FIG. 2 c), reaches over a bolt 40 of firstload abutment 14, via which lever 17 acts on first load abutment 14 inpivoting fashion and which serves to laterally separate the lever frommain compression spring 11. This further improves the compact design ofconstant bearer 1. In the lower position, discontinuity 39, belonging toauxiliary spring assembly 10, and first load abutment 14, accommodatingmain compression spring 11, thus engage each other and prevent, via maincompression spring 11, which is compressed to a desired minimum springlength, further downward movement of load-bearing part 3 beyond thelower travel position.

According to the cited prior art in EP 0 188 654 A1, auxiliarycompression spring assembly 20 can likewise be adjusted. Associatedfastening abutment 15 is set via a screw-type adjusting device 41 tothis end.

The following is a more detailed description of the second embodiment ofconstant bearer 1, which is shown in various views and a detail in FIGS.5 a to 8.

As in the first embodiment, the second embodiment displays a horizontalmain spring assembly 9 with a main compression spring assembly 9 alocated roughly perpendicularly to bearing force F, where maincompression spring assembly 9 a comprises two main compression springs11, between which cam part 12 is located. In contrast to the firstembodiment, however, the second embodiment of constant bearer 1 does notdisplay an auxiliary spring assembly as compensating device K. Instead,cam part 12 is designed as part of compensating device K. For loadtransmission from main spring assembly 9 to load-bearing part 3, campart 12 is coupled to main spring assembly 9 and load-bearing part 3.Due to the special design of the cam part, load-bearing part 3 and campart 12 can, according to the invention, be moved relative to each otheron a non-linear path in such a way that complete compensation of thechanging spring forces of main spring assembly 9 acting on load-bearingpart 3 is achievable when load-bearing part 3 moves along travel path w.

To this end, cam part 12 in this embodiment displays four leversdesigned as cam levers 42, each of which is mounted on fastening part 2in pivoting fashion in a pivoting plane including travel direction v andspring axis f. Cam levers 42 are designed as flat components with twonarrow, opposite side faces, a first side face 43 and a second side face44, where second side face 44 is in each case designed as a cam sideface 13. Pairs of cam levers 42 are combined as cam lever pairs 45 andassigned to one of main compression springs 11. Main compression springs11 are mounted in pivoting fashion on respectively associated cam leverpair 45 via a second load abutment 46 with a cross-bolt 47, wherecross-bolt 47 is rotatable, axially secured and engages a groove 48provided in the middle area of first side face 43. Via load rollers 49,load-bearing part 3 rests on cam side faces 13 in rolling fashion, wherea load roller 49 is assigned to each cam lever 42, and all load rollers49 are mounted in rotating fashion on a common load roller axle 50 withan axis of rotation d. The spring forces of main compression springs 11press, via second load abutment 46, against first side faces 43 of camlevers 42, which further transmit the spring forces to load-bearing part3 via load rollers 49 assigned to them.

FIG. 5 a shows load-bearing part 3 in an upper travel position, inwhich, as in the first embodiment, load-bearing part 3 is maximallyretracted into housing 5. In FIG. 5 b, load-bearing part 3 is shown in alower travel position, in which, as in the first embodiment,load-bearing part 3 is maximally extended from housing 5. Similarly,FIGS. 6 a and 6 c show constant bearer 1 with load-bearing part 3 in anupper and a lower travel position, but each in a side view in thisinstance. Additionally indicated in FIG. 6 c is a maximum travel path wof load-bearing part 3, over which it can be moved out of housing 5.

FIG. 6 b shows load-bearing part 3 in a middle travel position. Due tothe mounting of cam levers 42 on housing 5, the load side of maincompression springs 11, which, as in the first embodiment of constantbearer 1, are each mounted on housing 5 via a fastening abutment 15, isslightly pivoted on second load abutment 44 and with fastening abutment15 as the pivoting point. In this context, the geometries of constantbearer 1 are selected in such a way that, in the middle travel position,main compression springs 11 are perpendicular to travel direction v. Forattaching a load not shown here, an end of load-bearing part 3 designedas load-bearing end 51 passes out of housing 5 through a guide aperture52.

Via cam levers 42, a bearing force F, in this instance with a verticalforce component F_(s) in bearing force direction and a horizontal forcecomponent F_(h) in the direction of spring axis f and perpendicular toforce component F_(s), is exerted on the rollers in every travelposition of load-bearing part 3 on travel path w, where, thanks to thesymmetrical structure or thanks to the symmetrical arrangement of maincompression springs 11, the horizontal force components F_(h) canceleach other out and, together with the load (not shown) located onload-bearing end 51 of load-bearing part 3, ensure that the individualmoving parts of constant bearer 1 are held together. Cam side faces 13are profiled in such a way that force component F_(s) increases from thelower travel position to the upper travel position in continuous,non-linear fashion to a calculated extent in such a way that, when mainspring assembly 9 is compressed and relaxed, the changing spring forcesof main spring assembly 9, and the direction of spring axis f changed bythe above-mentioned pivoting of main compression springs 11 withpivoting of cam levers 42, are completely compensated for and a constantbearing force F acts on the load over travel path w. In qualitativeterms, bearing force F is roughly the sum of all vertical forcecomponents F_(s) on load rollers 49. It goes without saying that theforce arrows entered in FIGS. 6 a to 6 c as a bearing reaction of a camlever 42 on a load roller 49 as an example of bearing force F and forcecomponents F_(s) and F_(h) are only to be interpreted qualitatively anddo not indicate exact magnitudes.

The compactness of the design is improved in that, as can particularlybe seen in FIGS. 5 a and 5 b, cam lever pairs 45 mesh in tong-likefashion on the way from the lower to the upper travel position, in thattheir respective cam side faces 13 roll on one of load rollers 49, whichare mounted in rotating fashion on common load roller axle 50 and onwhich they are supported. Except in the area where cam levers 42 arelinked to housing 5, the outer profile of cam levers 42 is of roughlysickle or banana-shaped design, this catering to the anticipated forceand moment profile in cam lever 42 with a view to material minimisation.

As explained above, when main spring assembly 9 is set in the workingposition of the constant bearer, a permanent spring force of springsystem 4 is exerted on the load. In the absence of a load, e.g. duringtransport or storage of the constant bearer, load-bearing part 3 wouldbe accelerated against the load-bearing force with the force intendedfor bearing the pipeline. Therefore, a transport lock 53 with a toothedplate 54, shown in FIGS. 7 a and 7 b, is provided for a constant bearerwhen not in use. It can be fitted on load roller axis 50, extendingthrough a third guide slit 37, and, when placed between two toothedrails 55 provided on housing 5, engages said rails and thus blocksmovement of load-bearing part 3 on the travel path. Toothed plate 54 canbe removed when the load is attached to load-bearing end 51 (FIG. 7 b).

This transport lock 53 is also provided for the first embodiment, butomitted in FIGS. 1 to 5 for the sake of clarity.

Fastening abutment 15 and second load abutment 46 of the secondembodiment are in principle designed to be adjustable in the same way asfastening abutment 15 and first load abutment 14 of the firstembodiment. Similarly, a load scale 38 is also provided for more exactsetting of the respective main compression spring 11. Owing to thesymmetrical structure, only one load scale 38 is necessary for both maincompression springs 11. As can be seen in the detail view in FIG. 8, anamended version of sleeve 24 is provided, which is in this instanceadvantageously of smaller design, thus facilitating assembly.

LIST OF REFERENCE NUMBERS

-   1 Constant bearer-   2 Fastening part-   3 Load-bearing part-   4 Spring system-   5 Housing-   6 Side wall-   7 Connecting strap-   8 Fastening hole-   9 Main spring assembly-   9 a Main compression spring assembly-   10 Auxiliary spring assembly-   11 Main compression spring-   12 Cam part-   13 Cam side face-   14 First load abutment-   15 Fastening abutment-   16 Roller-   17 Lever-   18 Bolt-   19 Opening-   20 Auxiliary compression spring assembly-   21 Auxiliary cam part-   22 Pivoted lever-   23 Abutment disc-   24 Sleeve-   25 Through-hole-   26 Internal thread-   27 Bolt-   28 External thread-   29 Journal-   30 Bearing opening-   31 Operating end-   32 Retaining ring-   33 Stop hole-   34 Second guide projection-   35 Second guide slit-   36 Third guide slit-   37 Third guide projection-   38 Load scale-   39 Discontinuity-   40 Bolt-   41 Screw-type adjusting device-   42 Cam lever-   43 First side face-   44 Second side face-   45 Cam lever pair-   46 Second load abutment-   47 Cross-bolt-   48 Groove-   49 Load roller-   50 Load roller axle-   51 Load-bearing end-   52 Guide aperture-   53 Transport lock-   54 Toothed plate-   55 Toothed rail-   d Axis of rotation-   F Bearing force-   F_(s) Vertical force component-   F_(h) Horizontal force component-   f Spring axis-   K Compensating device-   t Bearing force direction-   v Travel direction-   w Travel path

The invention claimed is:
 1. Constant bearer for moving loads, especially pipelines and similar, comprising a fastening part, a load-bearing part, and a spring system located between the fastening part and the load-bearing part for generating a constant bearing force, where the spring system displays a main spring assembly absorbing the load and a compensating device to compensate for changing spring forces of the main spring assembly on the load-bearing part, wherein the main spring assembly comprises main compression springs disposed opposite each other, wherein the compensating device displays at least one cam part, in that the cam part is coupled to the main spring assembly and the load-bearing part for load transmission from the main spring assembly to the load-bearing part, and in that, when the load-bearing part moves along a travel path, the load-bearing part and the cam part can move relative to each other on a non-linear path in such a way that complete compensation for the changing spring forces of the main spring assembly on the load-bearing part can be achieved, wherein the cam part includes at least one lever, designed as a cam lever and mounted on the fastening part in pivoting fashion, with two opposite side faces in its longitudinal extension, a first side face and a second side face, in that the load side of the main spring assembly is mounted on the first side face in pivoting fashion, and in that the second side face is designed as a concave cam side face, on which the load-bearing part rests and moves over the whole travel path of the load-bearing part, and is decreasingly deflected, over the whole travel path, away from an end of the load-bearing part for application of the load.
 2. Constant bearer according to claim 1, wherein the main spring assembly displays a main compression spring assembly located roughly perpendicularly to the bearing force.
 3. Constant bearer according to claim 1, wherein the load-bearing part displays a load roller with an axis of rotation perpendicular to the spring axis and perpendicular to the bearing force direction, and in that the cam side face rests on the load roller in a plane perpendicular to the axis of rotation.
 4. Constant bearer according to claim 1, wherein the main compression spring assembly displays two main compression springs, the load sides of which act symmetrically on the load-bearing part.
 5. Constant bearer according to claim 4, wherein the main compression springs are located on a common spring axis, and in that the main compression springs lying opposite each other are supported on the cam part on the load side and on the fastening part of a fastening side.
 6. Constant bearer according to claim 5, wherein the cam part is located between the main compression springs.
 7. Constant bearer according to claim 4, wherein the cam part displays an associated cam side face for each main compression spring.
 8. Constant bearer according to claim 4 wherein the cam part is designed as a plate-like component with narrow side faces, where the two cam side faces are formed by two opposite, symmetrically arranged narrow side faces.
 9. Constant bearer according to claim 4, wherein the cam side faces are separated from each other by a conical or roughly conical gap.
 10. Constant bearer according to claim 4, wherein the at least one lever comprises at least two levers and each main compression spring has at least one of the cam levers assigned to it, in that the main compression spring is supported in a load abutment in a supporting area of the first side face of the associated cam lever, in that the cam lever is, in an area removed from the supporting area in the bearing force direction, mounted on the fastening part in pivoting fashion in a pivoting plane parallel to or in the travel direction and the spring axis, and in that the cam side face of the cam lever rests on the load-bearing part in sliding or rolling fashion.
 11. Constant bearer according to claim 10, wherein a load roller is assigned to each cam lever, and in that the load rollers are located on a common load roller axle in rotating fashion.
 12. Constant bearer according to claim 4, wherein a guide provides direct linear guidance of the main compression springs in the direction of the spring axis.
 13. Constant bearer according to claim 4, wherein the at least one lever comprises at least one lever for each main compression spring, one end of which, or a middle area of which, is mounted on the load side of the respective main compression spring, and the other end of which is mounted on the fastening part in pivoting fashion at a pivoting point removed in the bearing force direction.
 14. Constant bearer according to claim 13, wherein the at least one lever for each main compression spring is mounted in such a way that it runs parallel to the bearing force direction at a middle point of the spring excursion.
 15. Constant bearer according to claim 13, wherein two levers are provided for each main compression spring which, running parallel to each other and lying opposite each other, are laterally mounted on the load end in pivoting fashion.
 16. Constant bearer according to claim 1, characterised by a setting device for setting a pre-tension of the main spring assembly.
 17. Constant bearer according to claim 16, wherein the main compression springs are each mounted in a fastening abutment and/or the load abutment designed to slide and be fixed in position in the direction of the spring axis.
 18. Constant bearer according to claim 17, wherein the abutments each display an abutment disc, on which the main compression spring is supported at the face end and which can be adjusted in sliding fashion in the direction of the spring axis by means of a screw-type device.
 19. Constant bearer according to claim 18, wherein the abutment disc of the fastening abutment displays a concentric through-hole with an internal thread, through which a bolt with an external thread mating with the internal thread is passed, where the face end of the bolt facing away from the main compression spring is mounted on the fastening part in rotating fashion.
 20. Constant bearer according to claim 19 wherein the face end of the bolt displays a journal with a smaller diameter than the bolt, which extends concentrically in the longitudinal direction and which, in installation position, extends through a bearing opening adapted to it in the fastening part and is provided with an operating end projecting beyond the bearing opening for application of a tool.
 21. Constant bearer according to claim 19, wherein the face end of the bolt facing towards the load-bearing part in installation position displays a laterally projecting stop running against a bearing opening to limit the adjusting travel.
 22. Constant bearer according to claim 19, wherein the abutment disc displays a lateral, second guide projection which, in order to indicate the relative position of the abutment disc, extends through the fastening part through a second guide slit extending in the direction of the spring axis.
 23. Constant bearer according to claim 22, wherein a load scale for reading-off the relative position of the second guide projection and/or for reading-off the preload is located on the outside of the second guide slit.
 24. Constant bearer according to claim 1, wherein the cam part or the load-bearing part displays a lateral, third guide projection that extends, perpendicularly to the spring axis and to the spring travel direction, through a third guide slit, provided in the fastening part and running in the direction of the spring axis, and rests in sliding fashion on the inside surfaces of the third guide slit for guidance. 